Differential effect of human interferon on normal and neoplastic T- and B-cell lymphocytes

The effect of human interferon (HIF) on the growth and function of normal and neoplastic proliferating human T and B cells was studied. Cell cycle analysis by flow-cytometry showed that up to 2000 units of HIF had little effect on the proliferating fraction (that is, the present S + G2 + M phases of the cell cycle) of normal T cells grown continuously wit growth-promoting factor from PHA-stimulated lymphocytes, while 500 units of HIF suppressed the percent S + G2 + M of the acute lymphocytic leukemia (ALL) T-cell line, MOLT, by 36%. Up to 2000 units of HIF had a moderate enhancing effect on the percent S + G2 + M of PWM-stimulated lymphocytes. In striking contrast, a single unit of HIF caused nearly 40% suppression of the percent S + G2 + M of Daudi, a Burkitt's lymphoma cell. One-thousand units of HIF did not decrease the number of antibody-forming normal cells, and up to 500 units of HIF did not inhibit the total Ig secreted by these cells. These results suggest that amounts of HIF affecting the proliferation of some neoplastic lymphoid cells has little effect on the proliferation of normal T and B cells. In addition, HIF does not appear to affect polyclonal induction of B-cell differentiation.